Iranian journal of immunology
Volume:16 Issue: 3, Summer 2019

 Macrophage polarization plays a critical role in determining the inflammatory states. Hepcidin is a key negative regulator of iron homeostasis and functions. Although hepcidin has been shown to affect ferroportin expression in macrophages, whether it affects macrophage polarization is still largely unknown. 

 To address whether hepcidin induces macrophage polarization. 

 The expression of iNOS and CD206, and the ratio of IFN-γ vs IL-4 in THP-1 derived macrophages upon hepcidin stimulation were evaluated. Further detected was the percentage of CD16+ M1, CD23+ M1, CD10+ M2 and CCL22+ M2 cells in monocyte derived macrophages. 

 M1 associated molecules were increased in hepcidin-treated cells, yet M2 associated molecules were increased when hepcidin was neutralized. Concomitantly, we observed a significant increase in IRF3 phosphorylation in hepcidin-stimulated cells. However, STAT6 phosphorylation with hepcidin was neutralized. 

 Hepcidin is able to induce macrophage polarization towards M1 type, and might be utilized as a potential M1 macrophage agonist in clinical practice.

Caused by bacterial, viral, and parasitic pathogens, diarrhea is the second leading cause of death among children under five. Two strains of E. coli, namely Enterotoxigenic, ETEC and Enterohemorrhagic EHEC are the most important causes of this disease in developing countries. EHEC is a major causative agent of bloody diarrhea and hemorrhagic uremic syndrome, while ETEC is the most important cause of diarrhea in neonates and travelers.

To evaluate the immunologic properties of a subunit vaccine candidate comprising the main immunogenic epitopes from these two bacterial strains.

The construct comprised of LTB and CfaB antigens from ETEC, and Intimin and Stx2B antigens from EHEC, was designed, analyzed and synthesized using bioinformatics methods. The chimeric gene was sub-cloned in the expression vector and expressed in E. coli host. The purified chimera protein was injected subcutaneously into the experimental animals. The production of specific antibodies was confirmed by immunological methods, and the protection capacity was evaluated by the challenge of immunized mice with the pathogenic bacteria.

Chimeric recombinant protein was able to increase IgG titer. Neutralization assay indicated that the antibodies generated against LtB moiety were able to neutralize ETEC toxin. In animal challenge study, all non-immune mice died within 3 days after the injection of toxin, but all immunized mice survived from Stx toxin.

The immunity to both ETEC and EHEC bacteria is significant, and this structure can be considered as a candidate for vaccine production against these bacterial strains.

Shigella flexneri is a pathogen responsible for shigellosis around the world, especially in developing countries. Many immunogenic antigens have been introduced as candidate vaccines against Shigella, including N-terminal region of IpaD antigen (NIpaD).

To evaluate the efficiency of O-metylated free trimethyl chitosan nanoparticles (TMC NPs) in the oral delivery of NIpaD.

TMC was synthesized by a two-step method from high molecular weight chitosan. The recombinant NIpaD protein was used as the immunogen. The protein was overexpressed in E. coli BL21 (DE3) and characterized by gel electrophoresis. The NIpaD-loaded TMC NPs were synthesized by ionic gelation method and were characterized by electron microscopy. NPs were orally administered to guinea pigs and specific humoral and mucosal immune responses were assessed by serum IgG and secretory IgA, respectively. The protectivity of the formulation was assessed by keratoconjunctivitis (Sereny) test.

The immunized guinea pigs showed a significant raise in rNIpaD-specific serum IgG and faecal IgA titers. Specific secretory IgA was detected in eye-washes. Sereny test results showed that immunized animals vaccinated with IpaDloaded TMC NPS tolerated the wild type of Shigella flexneri 2a in Sereny test. However, in the group immunized with NIpaD antigen and non-immunized group, no increase was observed in antibody titer against NIpaD. These animals were infected following the challenge with Shigella flexneri 2a (p<0.0152).

The recombinant rNIpaD formulated with TMC obtained from high molecular weight chitosan, can be considered as a mucosal vaccine against Shigella flexneri through oral route.

Despite primary vaccination, infants under six months run a risk of infection with pertussis.

To determine the impact of early postpartum maternal pertussis vaccination on protecting infants from the disease.

All mothers (n=405) who gave birth to healthy term infants were educated on the cocoon strategy. The mothers who consented were immunized with the tetanus-diphtheriaacellular pertussis vaccine within the first three postpartum days. All infants received their pertussis vaccines according to the national schedule. The anti-pertussis IgG titers of infants of thirty vaccinated mothers were compared with those of thirty unvaccinated mothers.

The pertussis antibody levels in the infants of vaccinated mothers were significantly higher than those of unvaccinated mothers at the mean infant age of 5.6 ± 1.2 months. Only 6 infants of vaccinated mothers exhibited pertussis-like symptoms, none of whom had positive pertussis PCR. Seventeen infants of unvaccinated mothers had pertussis-like symptoms, and 4 tested positive for pertussis PCR.

Our results showed that maternal pertussis vaccination, administered within the first three postpartum days, may protect infants against pertussis in their first ten months.

Human colorectal cancer cells overexpress carcinoembryonic antigen (CEA). CEA is a glycoprotein which has shown to be a promising vaccine target for immunotherapy against colorectal cancer.

To design a DNA vaccine harboring CEA antigen and evaluate its effect on inducing immunity against colorectal cancer cells in tumor bearing mice.

In the first step the coding sequence of the CEA was cloned into the pcDNA3.1 vector. The mice were injected with the vaccine construct and the immune responses were monitored during the experiment period. The specific IgG anti-CEA, IFN-γ, IL-2 and IL-4 were measured by ELISA and levels of IFN-γ was detected by ELISpot assay. The lymphocyte proliferation was assessed using a 5-bromo-2-deoxyuridine (BrdU) cell proliferation assay kit.

Immunization of the mice with the CEA plasmid resulted in stimulation of CEAspecific T cell and antibody responses. The serum level of specific IgG antibodies against CEA was increased in immunized mice. Moreover, the injection of CEA plasmid led to the stimulation of T-helper-1 by increase in the secretion of IFN-γ, IL-2 and lymphocyte proliferation response.

As the CEA DNA vaccine displayed encouraging antitumor effects, therefore, we suggest that it can be a potential therapeutic modality for colorectal cancer and is worthy of further investigation.

Colorectal cancer (CRC) is attributed as one of the most common malignancies worldwide. CD133 molecule, as a pentaspan transmembrane glycoprotein, confers stem cell-related characteristics, including self-renewal and multi-directional differentiation capability. CD133 plays important roles in the progression of CRC by conferring apoptotic resistance and migration ability.

To investigate the antiapoptotic and anti-angiogenic effect of CD-133 targeted siRNA in a colorectal cancer cell line.

In this study, CD133-targeted siRNA transfection was conducted into HT-29 cells. MTT assay was employed to evaluate the cytotoxic effects of transfection on the cells. Flow cytometry was used to evaluate the apoptosis rate. The mRNA expression of apoptosis and metastasis related genes were assessed by quantitative Real-Time PCR (qRT-PCR). Wound healing assay was used to assess the migration potency of the infected cells.

Expression of CD133 was significantly downregulated after transfection of CD133-specific siRNA. Moreover, the rate of apoptosis was significantly increased after transfection. The migration potential of cells was diminished after transfection. siRNA delivery resulted in the modulation of expression of apoptosis and metastasis-related genes.

siRNA mediated targeting of CD133 could be considered as a promising approach to treat CRC through suppressing the cancerous behavior of tumor cells.

The diagnostic methods which are used for acute ocular toxoplasmosis are very important; if the treatment is delayed, it sometimes leads to loss of vision. Few studies have been performed to evaluate serological tests used in the diagnosis of acute ocular toxoplasmosis.

To evaluate the immunoglobulin (Ig) M, G and IgG avidity tests for diagnosis of acute ocular toxoplasmosis in the northeast of Iran.

A cross-sectional study was carried out from January 2014 to December 2016. After an opthalmic examination was conducted by a retina specialist, 16 typical acute and 34 typical chronic ocular toxoplasmosis cases were included in this study. Information on clinical manifestations, age and occupation was recorded. AntiToxoplasma IgG, IgM and IgG avidity tests were administered on serum samples using the ELISA method.

Blurring of vision in all patients was the most clinical presentation. The IgG avidity test could diagnose all acute and recent cases. However, three false positive and one false negative result occurred using the IgM test by ELISA. The false negative result in all likelihood occurred because the patient was at the beginning stage of the infection.

The result of this study showed that IgM is not a reliable marker of acute disease. Repetition of the serology tests was proposed in cases with clinical manifestations without detectable antibody titer after approximately two weeks. IgG avidity testing results coincided with clinical diagnosis and it could therefore considered to be a reliable method to differentiate between recently acquired and chronic ocular toxoplasmosis.